Spy photographer Chris Doane for Brenda Priddy & Company caught a disguised 2008 Subaru WRX in testing this week in California. Previously, there have been several sightings of possible WRX test mules (in Legacy bodies). These pictures show an actual WRX prototype. The car is expected to take some inspiration from the Subaru B5 concept, though evidently not as much as one might expect. As for power, insiders are anticipating a big update to the 2.5-liter H4 turbo, with an output of around 330-horsepower. Priddy says the Impreza name could change for the 2008 model year. Gallery after the jump…